From: Dave Hansen People love to do comparisons with highmem_start_page. However, where CONFIG_HIGHMEM=y and there is no actual highmem, there's no real page at *highmem_start_page. That's usually not a problem, but CONFIG_NONLINEAR is a bit more strict and catches the bogus address tranlations. There are about a gillion different ways to find out of a 'struct page' is highmem or not. Why not just check page_flags? Just use PageHighMem() wherever there used to be a highmem_start_page comparison. Then, kill off highmem_start_page. This removes more code than it adds, and gets rid of some nasty #ifdefs in .c files. Signed-off-by: Dave Hansen Signed-off-by: Andrew Morton --- 25-akpm/arch/i386/mm/discontig.c | 5 ----- 25-akpm/arch/i386/mm/highmem.c | 6 +++--- 25-akpm/arch/i386/mm/init.c | 1 - 25-akpm/arch/i386/mm/pageattr.c | 5 +---- 25-akpm/arch/mips/mm/highmem.c | 6 +++--- 25-akpm/arch/mips/mm/init.c | 1 - 25-akpm/arch/ppc/mm/init.c | 1 - 25-akpm/arch/sparc/mm/highmem.c | 2 +- 25-akpm/arch/sparc/mm/init.c | 2 -- 25-akpm/arch/um/kernel/mem.c | 2 -- 25-akpm/include/asm-ppc/highmem.h | 6 +++--- 25-akpm/include/asm-sparc/highmem.h | 4 ++-- 25-akpm/include/linux/highmem.h | 2 -- 25-akpm/mm/memory.c | 2 -- 25-akpm/net/core/dev.c | 2 +- 15 files changed, 14 insertions(+), 33 deletions(-) diff -puN arch/i386/mm/discontig.c~kill-off-highmem_start_page arch/i386/mm/discontig.c --- 25/arch/i386/mm/discontig.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/arch/i386/mm/discontig.c Wed Nov 17 14:17:42 2004 @@ -464,11 +464,6 @@ void __init set_highmem_pages_init(int b void __init set_max_mapnr_init(void) { #ifdef CONFIG_HIGHMEM - struct zone *high0 = &NODE_DATA(0)->node_zones[ZONE_HIGHMEM]; - if (high0->spanned_pages > 0) - highmem_start_page = high0->zone_mem_map; - else - highmem_start_page = pfn_to_page(max_low_pfn - 1) + 1; num_physpages = highend_pfn; #else num_physpages = max_low_pfn; diff -puN arch/i386/mm/highmem.c~kill-off-highmem_start_page arch/i386/mm/highmem.c --- 25/arch/i386/mm/highmem.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/arch/i386/mm/highmem.c Wed Nov 17 14:17:42 2004 @@ -3,7 +3,7 @@ void *kmap(struct page *page) { might_sleep(); - if (page < highmem_start_page) + if (!PageHighMem(page)) return page_address(page); return kmap_high(page); } @@ -12,7 +12,7 @@ void kunmap(struct page *page) { if (in_interrupt()) BUG(); - if (page < highmem_start_page) + if (!PageHighMem(page)) return; kunmap_high(page); } @@ -32,7 +32,7 @@ void *kmap_atomic(struct page *page, enu /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ inc_preempt_count(); - if (page < highmem_start_page) + if (!PageHighMem(page)) return page_address(page); idx = type + KM_TYPE_NR*smp_processor_id(); diff -puN arch/i386/mm/init.c~kill-off-highmem_start_page arch/i386/mm/init.c --- 25/arch/i386/mm/init.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/arch/i386/mm/init.c Wed Nov 17 14:17:42 2004 @@ -549,7 +549,6 @@ void __init test_wp_bit(void) static void __init set_max_mapnr_init(void) { #ifdef CONFIG_HIGHMEM - highmem_start_page = pfn_to_page(highstart_pfn); max_mapnr = num_physpages = highend_pfn; #else max_mapnr = num_physpages = max_low_pfn; diff -puN arch/i386/mm/pageattr.c~kill-off-highmem_start_page arch/i386/mm/pageattr.c --- 25/arch/i386/mm/pageattr.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/arch/i386/mm/pageattr.c Wed Nov 17 14:17:42 2004 @@ -105,10 +105,7 @@ __change_page_attr(struct page *page, pg unsigned long address; struct page *kpte_page; -#ifdef CONFIG_HIGHMEM - if (page >= highmem_start_page) - BUG(); -#endif + BUG_ON(PageHighMem(page)); address = (unsigned long)page_address(page); kpte = lookup_address(address); diff -puN arch/mips/mm/highmem.c~kill-off-highmem_start_page arch/mips/mm/highmem.c --- 25/arch/mips/mm/highmem.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/arch/mips/mm/highmem.c Wed Nov 17 14:17:42 2004 @@ -8,7 +8,7 @@ void *__kmap(struct page *page) void *addr; might_sleep(); - if (page < highmem_start_page) + if (!PageHighMem(page)) return page_address(page); addr = kmap_high(page); flush_tlb_one((unsigned long)addr); @@ -20,7 +20,7 @@ void __kunmap(struct page *page) { if (in_interrupt()) BUG(); - if (page < highmem_start_page) + if (!PageHighMem(page)) return; kunmap_high(page); } @@ -41,7 +41,7 @@ void *__kmap_atomic(struct page *page, e /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ inc_preempt_count(); - if (page < highmem_start_page) + if (!PageHighMem(page)) return page_address(page); idx = type + KM_TYPE_NR*smp_processor_id(); diff -puN arch/mips/mm/init.c~kill-off-highmem_start_page arch/mips/mm/init.c --- 25/arch/mips/mm/init.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/arch/mips/mm/init.c Wed Nov 17 14:17:42 2004 @@ -204,7 +204,6 @@ void __init mem_init(void) unsigned long tmp, ram; #ifdef CONFIG_HIGHMEM - highmem_start_page = mem_map + highstart_pfn; #ifdef CONFIG_DISCONTIGMEM #error "CONFIG_HIGHMEM and CONFIG_DISCONTIGMEM dont work together yet" #endif diff -puN arch/ppc/mm/init.c~kill-off-highmem_start_page arch/ppc/mm/init.c --- 25/arch/ppc/mm/init.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/arch/ppc/mm/init.c Wed Nov 17 14:17:42 2004 @@ -419,7 +419,6 @@ void __init mem_init(void) unsigned long highmem_mapnr; highmem_mapnr = total_lowmem >> PAGE_SHIFT; - highmem_start_page = mem_map + highmem_mapnr; #endif /* CONFIG_HIGHMEM */ max_mapnr = total_memory >> PAGE_SHIFT; diff -puN arch/sparc/mm/highmem.c~kill-off-highmem_start_page arch/sparc/mm/highmem.c --- 25/arch/sparc/mm/highmem.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/arch/sparc/mm/highmem.c Wed Nov 17 14:17:42 2004 @@ -36,7 +36,7 @@ void *kmap_atomic(struct page *page, enu /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ inc_preempt_count(); - if (page < highmem_start_page) + if (!PageHighMem(page)) return page_address(page); idx = type + KM_TYPE_NR*smp_processor_id(); diff -puN arch/sparc/mm/init.c~kill-off-highmem_start_page arch/sparc/mm/init.c --- 25/arch/sparc/mm/init.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/arch/sparc/mm/init.c Wed Nov 17 14:17:42 2004 @@ -402,8 +402,6 @@ void __init mem_init(void) int reservedpages = 0; int i; - highmem_start_page = pfn_to_page(highstart_pfn); - if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) { prom_printf("BUG: fixmap and pkmap areas overlap\n"); prom_printf("pkbase: 0x%lx pkend: 0x%lx fixstart 0x%lx\n", diff -puN arch/um/kernel/mem.c~kill-off-highmem_start_page arch/um/kernel/mem.c --- 25/arch/um/kernel/mem.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/arch/um/kernel/mem.c Wed Nov 17 14:17:42 2004 @@ -49,8 +49,6 @@ static void setup_highmem(unsigned long unsigned long highmem_pfn; int i; - highmem_start_page = virt_to_page(highmem_start); - highmem_pfn = __pa(highmem_start) >> PAGE_SHIFT; for(i = 0; i < highmem_len >> PAGE_SHIFT; i++){ page = &mem_map[highmem_pfn + i]; diff -puN include/asm-ppc/highmem.h~kill-off-highmem_start_page include/asm-ppc/highmem.h --- 25/include/asm-ppc/highmem.h~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/include/asm-ppc/highmem.h Wed Nov 17 14:17:42 2004 @@ -56,7 +56,7 @@ extern void kunmap_high(struct page *pag static inline void *kmap(struct page *page) { might_sleep(); - if (page < highmem_start_page) + if (!PageHighMem(page)) return page_address(page); return kmap_high(page); } @@ -64,7 +64,7 @@ static inline void *kmap(struct page *pa static inline void kunmap(struct page *page) { BUG_ON(in_interrupt()); - if (page < highmem_start_page) + if (!PageHighMem(page)) return; kunmap_high(page); } @@ -82,7 +82,7 @@ static inline void *kmap_atomic(struct p /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ inc_preempt_count(); - if (page < highmem_start_page) + if (!PageHighMem(page)) return page_address(page); idx = type + KM_TYPE_NR*smp_processor_id(); diff -puN include/asm-sparc/highmem.h~kill-off-highmem_start_page include/asm-sparc/highmem.h --- 25/include/asm-sparc/highmem.h~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/include/asm-sparc/highmem.h Wed Nov 17 14:17:42 2004 @@ -57,7 +57,7 @@ extern void kunmap_high(struct page *pag static inline void *kmap(struct page *page) { BUG_ON(in_interrupt()); - if (page < highmem_start_page) + if (!PageHighMem(page)) return page_address(page); return kmap_high(page); } @@ -65,7 +65,7 @@ static inline void *kmap(struct page *pa static inline void kunmap(struct page *page) { BUG_ON(in_interrupt()); - if (page < highmem_start_page) + if (!PageHighMem(page)) return; kunmap_high(page); } diff -puN include/linux/highmem.h~kill-off-highmem_start_page include/linux/highmem.h --- 25/include/linux/highmem.h~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/include/linux/highmem.h Wed Nov 17 14:17:42 2004 @@ -9,8 +9,6 @@ #ifdef CONFIG_HIGHMEM -extern struct page *highmem_start_page; - #include /* declarations for linux/mm/highmem.c */ diff -puN mm/memory.c~kill-off-highmem_start_page mm/memory.c --- 25/mm/memory.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/mm/memory.c Wed Nov 17 14:17:42 2004 @@ -76,11 +76,9 @@ unsigned long num_physpages; * and ZONE_HIGHMEM. */ void * high_memory; -struct page *highmem_start_page; unsigned long vmalloc_earlyreserve; EXPORT_SYMBOL(num_physpages); -EXPORT_SYMBOL(highmem_start_page); EXPORT_SYMBOL(high_memory); EXPORT_SYMBOL(vmalloc_earlyreserve); diff -puN net/core/dev.c~kill-off-highmem_start_page net/core/dev.c --- 25/net/core/dev.c~kill-off-highmem_start_page Wed Nov 17 14:17:42 2004 +++ 25-akpm/net/core/dev.c Wed Nov 17 14:17:42 2004 @@ -1119,7 +1119,7 @@ static inline int illegal_highdma(struct return 0; for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) - if (skb_shinfo(skb)->frags[i].page >= highmem_start_page) + if (PageHighMem(skb_shinfo(skb)->frags[i].page)) return 1; return 0; _